Sweet Onion BBQ Burgers (Taste of Home)

1/2 cup dry bread crumbs
2 teaspoons onion salt
2 teaspoons brown sugar
1 egg, lightly beaten
1 pound ground beef
1-1/4 cups barbecue sauce
SAUCE:
1/2 cup mayonnaise
1/2 cup barbecue sauce
1 teaspoon brown sugar
ONION TOPPING:
2 tablespoons butter
1/4 cup honey
2 large sweet onions, thinly sliced
4 slices smoked cheddar cheese
4 hamburger buns, split

In a large bowl, combine the bread crumbs, onion salt and brown sugar. Add egg. Crumble beef over mixture and mix well. Shape into four patties. Place in a shallow dish; pour barbecue sauce over patties. Cover and refrigerate for 2-4 hours.
In a small bowl, combine the sauce ingredients; cover and refrigerate until serving. For topping, melt butter in a small skillet. Stir in honey until blended. Add onions; saute for 15-20 minutes or until tender and lightly browned. Remove from the heat and keep warm.
Drain and discard barbecue sauce. Grill patties, uncovered, over medium heat or broil 4 in from the heat for 5-7 minutes on each side or until a thermometer reads 160° and juices run clear. Top each with a cheese slice; cook 1 minute longer or until cheese is melted. Serve on buns with sauce and onion topping. Yield: 4 servings.